What is the primary cause of valves sticking in an engine?

The primary cause of valves sticking in an engine is gum accumulation. This occurs due to the build-up of deposits that can form from the combustion process and the breakdown of engine oil over time. When engine oil degrades, it can leave behind sticky residues, which can eventually harden and create a barrier around the valve. This barrier interferes with the smooth operation of the valve, causing it to stick, which can lead to poor engine performance or even engine damage.

While improper lubrication, excessive heat, and corrosion can all contribute to engine issues, they are not the main cause of valve sticking. Improper lubrication may lead to other problems, such as increased wear and tear or overheating, while excessive heat can cause warping and distortion of engine components rather than directly leading to valve sticking. Corrosion from chemicals can certainly impact various parts of an engine but is less likely to specifically cause valves to stick compared to the effects of gum accumulation and the resulting residues that interfere with proper valve movement.